HarmonyOS 倒计时天数

dateDiff(startDate:Date,endDate:Date){  
  const oneDay = 24 * 60 * 60 * 1000; // 一天的毫秒数  
  // 将时间戳转换为整数天数  
  const start = Math.floor(startDate.getTime() / oneDay);  
  const end = Math.floor(endDate.getTime() / oneDay);  
  const difference = end - start; // 计算差值天数  
  return difference;  
}  
const difference = this.dateDiff(new Date('2023-01-01'), new Date('2023-01-10'));  
console.log(difference + ""); //输出 9